Abstract
Humanoids now walk, balance and reach with remarkable generality: one whole-body tracking policy follows references from a human, or from an end-to-end policy. That generality travels in the trajectory, and a trajectory alone carries limited information about the interaction it should produce: at contact, the executing controller determines how the robot behaves. Single-task policies usually reach hard interactions by optimising trajectory and controller together in simulation; general stacks usually assume a preset or hand-chosen controller. We present KPI, a promptable kernel for physical interaction between the trajectory source and an unmodified whole-body tracker. Instead of a controller fixed before the task, the trajectory source sends a contract: per direction, track, comply, or hold a force range. From tracking error and a wrench estimate, the kernel adapts the arms' stiffness, damping, reference and feedforward toward it at contact rate. We demonstrate KPI through an agentic framework: from one instruction, a vision-language agent writes both the reference trajectory and the contract, with no task-specific code. We demonstrate instruction-driven winch operation, door opening, and box transport, alongside scripted surface-interaction experiments. In the winch demonstration, the humanoid is able to turn a crank to hoist a second robot fully off the ground.
Keywords
Publication details
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- Open access
- Green open access
Cite this article
APA 7
Wang, Y., Zhu, H., Hu, X., Zhang, H., Wang, Z., Yeung, Y. F., Zhao, D., & Sun, L. (2026). KPI: A Promptable Kernel for Physical Interaction on Humanoids. https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids
MLA 9
Wang, Yikai, et al. "KPI: A Promptable Kernel for Physical Interaction on Humanoids." https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids.
Chicago (author–date)
Wang, Yikai, Honghao Zhu, Xiao Hu, Hao Zhang, Zelin Wang, Yip Fun Yeung, Ding Zhao, and Lingfeng Sun. 2026. "KPI: A Promptable Kernel for Physical Interaction on Humanoids." https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids.
Harvard
Wang, Y., Zhu, H., Hu, X., Zhang, H., Wang, Z., Yeung, Y. F., Zhao, D. and Sun, L. (2026) 'KPI: A Promptable Kernel for Physical Interaction on Humanoids', Available at: https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids.
Vancouver
Wang Y, Zhu H, Hu X, Zhang H, Wang Z, Yeung YF, et al. KPI: A Promptable Kernel for Physical Interaction on Humanoids. https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids
IEEE
Y. Wang, H. Zhu, X. Hu, H. Zhang, Z. Wang, Y. F. Yeung, D. Zhao, and L. Sun, "KPI: A Promptable Kernel for Physical Interaction on Humanoids," https://omanscience.com/en/articles/kpi-a-promptable-kernel-for-physical-interaction-on-humanoids.